Analyzing the Distribution of Seismic Velocity Structures at an Established Contaminant Plume Using Compressional and Shear Wave Velocity Modeling

Abstract

Landfill leachate plumes have been a major environmental concern because of their ability in contaminating shallow groundwater aquifers. Leachate plumes transport toxic materials, which are hazardous to groundwater resources. The Norman landfill research site is a closed municipal solid waste landfill, formerly operated by the city of Norman, OK. Current study was conducted to show the utility of VP and VS modeling for contaminant plume characterization. To achieve the goal, we acquired a set of vertical component seismic data with 48 channels. The receiver spacing was 8ft (2.4m) and the shots were located at each receiver. 43 shots were recorded along a 376 ft (114.5m) long profile from SE to NW of the profile. We performed the travel time tomography for VP and surface wave inversion for VS modeling. Overall, both VP and VS models represent a smooth variation over the interpreted plume. However, VP shows a decrease and VS shows a gentle increase of velocities around the plume. In the next phase, we plan to carry out VP/VS and seismic velocity-driven Poisson’s ratio models to gain better understanding of the mechanical state of the medium due to the presence of the contaminants.